Prioritized serial communication

Abstract

An electric system for transmitting serial communication messages with different priorities over a communication link. The data to be transmitted is arranged in serial communication messages comprising a start of packet (SOP) symbol and data symbols. The ongoing transmission of a first message is interrupted if a SOP symbol of a second message is sent before the first message has been completed. Transmission of the first message is continued only after the second message has been sent.

What is claimed is: 
     
       1. A method for transmitting serial communication messages with different priorities over a communication link, comprising:
 enabling each message to comprise a start of packet (SOP) symbol and a plurality of data symbols, 
 interrupting transmission of a first message if the SOP symbol of a second message is sent before the first message has been completed, and 
 continuing the transmission of the first message from a point where the first message was interrupted only after the second message has been transmitted, 
 wherein: 
 the transmission of the second message is interrupted if the SOP symbol of a third message is sent before the second message has been completed, 
 the transmission of the second message is continued only after the third message has been completely transmitted, 
 the third message has higher priority than the second message, and the second message has higher priority than the first message, 
 each symbol of each of the serial communication messages comprises a predefined number of bits, and 
 the serial communication messages are encoded such that information on the plurality of data symbols in a message is included in a first symbol of the message, wherein the first symbol is part of the plurality of data symbols, and wherein the plurality of data symbols follow the SOP symbol. 
 
     
     
       2. The method according to  claim 1 , wherein the each message comprises an end of packet (EOP) symbol. 
     
     
       3. The method according to  claim 1 , wherein the transmission of the first message is continued only after the second message has been transmitted in its entirety. 
     
     
       4. The method according to  claim 1 , wherein, at a signal receiving end of the communication link, data symbols of the first message sent before the first message was interrupted by the second message and data symbols of the first message sent after the first message was interrupted by the second message are reconstructed into a single message. 
     
     
       5. The method according to  claim 1 , wherein the first message and the second message are transmitted over a single physical communication link. 
     
     
       6. The method according to  claim 1 , wherein each symbol of the each message is in 8b/10b line code. 
     
     
       7. An apparatus for transmitting serial communication messages with different priorities over a communication link, the apparatus comprising a first processor configured to:
 encode the serial communication messages such that each message comprises a start of packet (SOP) symbol and a plurality of data symbols, 
 interrupt transmission of a first message if the SOP symbol of a second message is sent before the first message has been completed, and 
 continue the transmission of the first message from a point where the first message was interrupted only after the second message has been transmitted, 
 wherein: 
 the transmission of the second message is interrupted if the SOP symbol of a third message is sent before the second message has been completed, 
 the transmission of the second message is continued only after the third message has been completely transmitted, 
 the third message has higher priority than the second message, and the second message has higher priority than the first message, 
 each symbol of each of the serial communication messages comprises a predefined number of bits, and 
 the serial communication messages are encoded such that information on the plurality of data symbols in a message is included in a first symbol of the message, wherein the first symbol is part of the plurality of data symbols, and wherein the plurality of data symbols follow the SOP symbol. 
 
     
     
       8. The apparatus as claimed in  claim 7 , the apparatus being further configured to encode the serial communication messages such that the each message comprises an end of packet (EOP) symbol. 
     
     
       9. The apparatus according to  claim 7 , the apparatus further comprising a second processor configured to reconstruct data symbols of the first message sent before the first message was interrupted by the second message and data symbols of the first message sent after the first message was interrupted by the second message into a single message. 
     
     
       10. The apparatus according to  claim 7 , wherein the first processor has a predefined function. 
     
     
       11. The apparatus according to  claim 7 , wherein operation of the first processor is based on a downloadable software. 
     
     
       12. The apparatus according to  claim 7 , the apparatus is a power electronic converter. 
     
     
       13. The apparatus according to  claim 7 , wherein the first message and the second message are transmitted over a single physical communication link. 
     
     
       14. The apparatus according to  claim 7 , wherein each symbol of the each message is in 8b/10b line code. 
     
     
       15. A computer program product comprising a non-transitory computer readable medium encoded with a computer program configured to implement a method of:
 encoding serial communication messages such that each message comprises a start of packet (SOP) symbol and a plurality of data symbols, 
 interrupting transmission of a first message if the SOP symbol of a second message is sent before the first message has been completed, and 
 continuing the transmission of the first message from a point where the first message was interrupted only after the second message has been transmitted, 
 wherein: 
 the transmission of the second message is interrupted if the SOP symbol of a third message is sent before the second message has been completed, 
 the transmission of the second message is continued only after the third message has been completely transmitted, 
 the third message has higher priority than the second message, and the second message has higher priority than the first message, 
 each symbol of each of the serial communication messages comprises a predefined number of bits, and 
 the serial communication messages are encoded such that information on the plurality of data symbols in a message is included in a first symbol of the message, wherein the first symbol is part of the plurality of data symbols, and wherein the plurality of data symbols follow the SOP symbol. 
 
     
     
       16. The computer program product according to  claim 15 , wherein the first message and the second message are transmitted over a single physical communication link.